Rectangular or box-shaped ducts are extensively utilized in heating, air conditioning, and ventilating systems to distribute heated or cooled air throughout a structure. These ducts are commonly formed from differing gauges of sheet metal in sections of predetermined lengths, which are then connected to one another to form a continuous duct for distributing air.
These ducts are typically composed of relatively short sections. Transverse flange frames are located at the ends of each section so that abutting sections may be bolted together at their corners with the flange frames held by clips or drive cleats. These frames are typically not integral to the duct section.
These types of flanges are well known and widely utilized. One type of such flanges are known as “slip-on” flanges. Slip-on flanges are roll formed and cut to a proper length. Then, four flange pieces and four corner pieces are assembled into a frame, which is attached to each end of a duct section. The duct sections can then be connected by joining the frames with mechanical fasteners. If one of the sides of the duct section is relatively long, then reinforcing bars may have to be added within the flanges to provide the necessary support strength. The addition of an extra part to the connecting system obviously increases the installation time for assembling the duct sections together.
With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a flange, which overcomes the above-described drawbacks while maximizing flange strength.